Setting a Default route in Express.js

Last Updated : 30 Nov, 2020

What is a default route?

As we know that in an express application, there are so many URLs and requests involved. It might be possible that the user hit a route which is not included in our express app. In that case, the user will get an error for handling these kinds of issues, we set a default route to our express app that informs the user that, he has hit a wrong route or redirect the user to a specific route.

The below is an example error page when a user hits a wrong route:

Follow these precautions while defining your default route:

There will be only one default route in your web app.
The default route will be defined after all other routes for the app are defined i.e. at the end.

Steps to set the default route in the express app:

Step 1: Create your project folder.

Step 2: Now in your terminal, run the following command from the root of your project folder:

 $ npm init

Step 3: Install express using the following command:

 $ npm install express

Step 4: Require 'express' and set your all general routes as per the requirements of your application.

Step 5: Below all routes, set your default route as shown below:

app.get("*", function (req, res) {
    res.render("Error_page");   
});

Example: An example of an express app with a default route given below.

Filename: index.js

JavaScript

// Requiring modules
const express = require("express");
const app = express();

// Root route of express app
app.get("/", (req, res) => {
  res.send("Hello Geeks");
});

app.get("/new", (req, res) => {
  res.send("welcome to new page");
});

// All the general routes of your
// web app are defined above the
// default route

// Default route
app.get("*", (req, res) => {

  // Here user can also design an
  // error page and render it 
  res.send("PAGE NOT FOUND");
});

// Server setup
app.listen(3001, () => {
  console.log(
`Server listening on http://localhost:3001`);
});

Run the index.js file using the following command:

node index.js

Output:

Server listening on http://localhost:3001

Now open your browser and navigate to http://localhost:3001, you will see the following message on screen:

Hello Geeks

Now hit any different URL other than our defined URL's, like here we have hit http://localhost:3001/xyz. Following will be the output on your screen: